“The Stapletons then went down to Devonshire, whither they were soon followed by Sir Henry and you. One word now as to how I stood myself at that time. It may possibly recur to your memory that when I examined the paper upon which the printed words were fastened I made a close inspection for the water-mark. In doing so I held it within a few inches of my eyes, and was conscious of a faint smell of the scent known as white jessamine. There are seventy-five perfumes, which it is very necessary that a criminal expert should be able to distinguish from each other, and cases have more than once within my own experience depended upon their prompt recognition. The scent suggested the presence of a lady, and already my thoughts began to turn towards the Stapletons. Thus I had made certain of the hound, and had guessed at the criminal before ever we went to the west country.
“It was my game to watch Stapleton. It was evident, however, that I could not do this if I were with you, since he would be keenly on his guard. I deceived everybody, therefore, yourself included, and I came down secretly when I was supposed to be in London. My hardships were not so great as you imagined, though such trifling details must never interfere with the investigation of a case. I stayed for the most part at Coombe Tracey, and only used the hut upon the moor when it was necessary to be near the scene of action. Cartwright had come down with me, and in his disguise as a country boy he was of great assistance to me. I was dependent upon him for food and clean linen. When I was watching Stapleton, Cartwright was frequently watching you, so that I was able to keep my hand upon all the strings.